Fairlight Cove Environmental Issues

Geological Interest

These coastal cliffs are of great geological importance.

There are 6 km of eroding seacliffs giving the furthest south easterly exposures of the lower Hastings Beds Group in the UK. These rocks are early Cretaceous in age and about 130 million years old. The section is continuous and extends from the basal Ashdown Sand Formation to the lower Wadhurst Clay Formation. The rocks and sediments exposed along the section provide evidence of the kinds of environments that existed when these rocks were deposited. These indicate that at that time, this part of Sussex formed the edge of a large fresh to brackish-water lake. Evidence of the rivers that supplied this lake may be seen in the form of delta deposits that developed where the coarser sediment carried by the rivers was deposited at the margins of the lake. Other sediments may be interpreted as alluvial plains on which meander belts were formed.

The eroding cliffs consist of Cretaceous sediments (Fairlight Clays, Ashdown Sands and Wadhurst Clay). The Wadhurst Clay (Lower Cretaceous) has produced many specimens of dinosaurs, pterosaurs, turtles, crocodiles and plesiosaurs. A classic collecting area, this is probably the best area for future finds of Lower Cretaceous reptiles outside the Isle of Wight. The Fairlight Cliffs also have a unique Lower Cretaceous mammal fauna. The site is remarkable for yielding teeth of Aegialodon dawsoni, a form close to the ancestry of modern therian mammals. It is one of a handful of localities in the world to have yielded early Cretaceous mammal remains.

In East Sussex the rocks form part of a gentle, crested upfold known as the Weald Anticline and dominate the geological structure of south eastern England. Contained within this structure are a complex pattern of faults, and at Fairlight, two coastal sections expose representative examples of these structures. At these localities two reverse faults cut the strata, the Haddocks and Fairlight Cove faults. Both are orientated WNW to ESE and are inclined steeply to the SSW. The displacements on these faults are substantial, being in the order of 50 metres downthrow to the NNE in each case. These faults are considered to be the surface expression of deep seated faults over which the Weald Anticline developed as a result of crustal compression during the Tertiary at the time of the Alpine mountain building episode (orogeny).

Source: http://www.english-nature.org.uk/citation/citation_photo/1002885.pdf